03 04 Subcommands - Clap

console

$ 03_04_subcommands_derive help
A simple to use, efficient, and full-featured Command Line Argument Parser

Usage: 03_04_subcommands_derive[EXE] <COMMAND>

Commands:
  add   Adds files to myapp
  help  Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

$ 03_04_subcommands_derive help add
Adds files to myapp

Usage: 03_04_subcommands_derive[EXE] add [NAME]

Arguments:
  [NAME]  

Options:
  -h, --help     Print help
  -V, --version  Print version

$ 03_04_subcommands_derive add bob
'myapp add' was used, name is: Some("bob")

When specifying commands with command: Commands, they are [required][crate::Command::subcommand_required]. By default, a missing subcommand will [show help rather than error][crate::Command::arg_required_else_help].

console

$ 03_04_subcommands_derive
? failed
A simple to use, efficient, and full-featured Command Line Argument Parser

Usage: 03_04_subcommands_derive[EXE] <COMMAND>

Commands:
  add   Adds files to myapp
  help  Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

To make a subcommand optional, wrap it in an Option (e.g. command: Option<Commands>).

Since we specified [#[command(propagate_version = true)]][crate::Command::propagate_version], the --version flag is available in all subcommands:

console

$ 03_04_subcommands_derive --version
clap [..]

$ 03_04_subcommands_derive add --version
clap-add [..]